Automatic merge from submit-queue

Abstraction of endpoints in leaderelection code

**Problem Statement**:
Currently the Leader Election code is hard coded against the endpoints api.  This causes performance issues on large scale clusters due to incessant iptables refreshes, see: https://github.com/kubernetes/kubernetes/issues/26637 

The goal of this PR is to: 

- Abstract Endpoints out of the leader election code
- Fix a known bug in the event recording 

fixes #18386

**Special notes for your reviewer**:
This is a 1st pass at abstracting the details of endpoints out into an interface.  Any suggestions around how we we want to refactor this interface is welcome and could be addressed in either this PR or follow on PR. 

/cc @ncdc @wojtek-t @rrati